


fiducia

by armethaumaturgy



Category: Undertale (Video Game)
Genre: Body Image, Cross (X-tale) - Freeform, Crossmare - Freeform, Ecto-Breasts (Undertale), Ecto-Genitalia (Undertale), M/M, Mild Sexual Content, Nightmare (Dreamtale) - Freeform, Praise Kink, cross/nightmare - Freeform
Language: English
Status: Completed
Published: 2021-02-04
Updated: 2021-02-04
Packaged: 2021-03-16 02:53:45
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,006
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29200158
Author URL: https://archiveofourown.org/users/armethaumaturgy/pseuds/armethaumaturgy
Summary: Cross’ preference was… probably the most obvious one. And while yes, one of the others was always more than willing to indulge him, Nightmare… was not.
Relationships: Sans/Sans (Undertale)
Comments: 4
Kudos: 173





	fiducia

**Author's Note:**

> this was written for neah, ily. i dont usually write bobbies so uh. yeah

Each of his boys had a preference, Nightmare knew. Some less obvious, some more so. And because he was a benevolent boss — because all these idiots belonged to him, were his responsibility — he’d always done his best to accommodate, even if it wasn’t all that obvious sometimes.

Cross’ preference was… probably the most obvious one. And while yes, one of the others was always more than willing to indulge him, Nightmare… was not. He stared down at the soldier from his perch on his lap, breath hitching at the feather-light touch across his ribs. Nightmare knew Cross would never ask him, not directly, but the wave of yearning he could practically taste rolling off of him was proof enough that he found Nightmare… lacking.

It did, admittedly, make him feel guilty. And his own negative emotions never felt as good as those of others. He huffed, forcing down his anger when Cross just kept teasing at his ribs, tracing their lengths with the tip of his phalanx, occasionally dipping between them to stroke the ecto-flesh beneath. Sure, the attention was sending sparks of pleasure up and down his spine, and his cunt was soaking through the fabric of his shorts, and, at this point, Cross’ too, but he made no move to advance the teasing.

Nightmare gripped Cross’ wrist on the next pass over his bottommost rib. He kept it at bay and stared down straight into those mismatched eyelights. CCross’ face was flushed an endearing shade of purple. “You should’ve gone to one of the others if this is what you’ve wanted,” he said. He was sure he’d kept the dejection out of his voice, but his expression, he wasn’t as sure of.

A burst of guilt from Cross hit him, rich like wine. That was his answer. Cross opened his mouth, most probably to apologize, but Nightmare was faster with his own sigh.

“Just this once.”

Cross stared at him with wide-blown sockets, his guilt mixing with trepidation as Nightmare gathered his magic. With little preamble, the magic solidified into a pair of breasts. They moved along with his next shaky breath.

It took him an embarrassing amount of self-control to keep his voice steady and level. “I’ll give you ten seconds. You may laugh.”

He averted his gaze and instead pointedly bore a hole through the wallpaper.

But instead of the expected disgust, Cross radiated confusion like a beacon. “Laugh?” he asked, like he hadn’t heard Nightmare clear as crystal the first time. “Night… Boss.” His free hand, the one that Nightmare wasn’t holding in a vice grip, came to rest on top of his phalanges. “Did you… I…? Why would I laugh?”

Nightmare glanced at him with a pointed look, socket narrowed. The breasts really  _ were  _ moving with each of his breaths, and he was hyper-aware of it. Cross turned his hand so he could hold it with both of his.

“I… think they’re pretty,” Cross admitted, purple all the way down to his cervical vertebrae. “Like the rest of you. And I’m sorry… for making you do something you’re not comfortable with.”

“They’re not.” Nightmare only addressed one part of that, because if he acknowledged Cross’ apology, he’d also have to acknowledge his own fear and insecurity. The day he did that would be his last.

“They are, Night.”

He huffed a laugh. “Right. Well, now that I’ve satiated your curiosity, I will return to my paperwork.”

He’d tried to get off of Cross’ lap, but was held back by a hand on his hip. Then he’d tried to disperse his chest, at least, but that was also halted by a hand, a gentle touch between them, over his sternum. His tentacles lashed wildly behind him, the only show of emotions he wouldn’t allow himself to express.

“Wait,” Cross said. His voice was as close to begging as it could get without the actual words. “Please.”

Something in Nightmare knotted up, like a lump in his disgusting, rotten SOUL. They stared at each other for long seconds, impassive versus concerned. Cross swallowed audibly and then his browbones furrowed.

“I meant it,” he said softly, as if he thought raising his voice would get him in trouble. From the tenseness of his shoulders and the worry radiating off of him, it probably wasn’t too far off of what he  _ did _ think. “I think you’re beautiful, boss.”

Cross’ hand moved from his sternum — where he’d no doubt felt the beating of his SOUL — to lay over one of his breasts. It barely fit in his hold, and Nightmare took a breath that was too shaky for his own likes.

“Let me show you, boss,” Cross demanded, when Nightmare had scoffed. His thumb ran across the ecto-flesh, circling around his nipple as if coaxing it out. Nightmare looked away, gritting his teeth, But Cross’ face wasn’t a much better place. Cross’ smile was soft, his eyesockets narrowed to go with it. “Let me worship you like you deserve.”

Nightmare wouldn’t admit it, especially not to Cross himself, but the soldier had quickly learned to read them all like a book. Nightmare wasn’t sure if it was his training, an ability to read people for their weaknesses, or just something he picked up from all of them. Whatever it was, Cross had the ability, and Nightmare was loath to admit it did wonders to calm him down. The words struck a chord in him, his innate need to be in control appreciative.

Cross’ thumb ran over his nipple again, sending a shiver through him.

He sighed and one of his tentacles curled around his other wrist. Cross paused his ministrations, looking up to see if Nightmare wanted him to stop. But the tentacle simply tugged his hand up towards his other breast.

Cross’ smile widened and he leaned up to brush their teeth together. It was soft, it was gentle, and most of all, it was  _ promising _ .

Hot breath fanned over his skull. “Let me serve you.”

So Nightmare closed his eye and let him.


End file.
